1. Field of the Invention
The present invention relates generally to still picture signal editing or processing method and apparatus thereof and, more particulary, to a still picture signal processing method and an apparatus thereof for use with a still picture signal communcation user terminal apparatus.
2. Description of the Prior Art
A prior-art still picture signal editing or processing apparatus applied to a still picture signal communication user terminal apparatus will hereinafter be described with reference to FIGS. 1 and 2.
An example of a prior-art still picture signal editing or processing apparatus that edits or processes a still picture signal by using two frame memories FR-M1 and FR-M2 will be described first with reference to FIG. 1.
A first input still picture signal (for example, a still picture signal representing "A") is written in one frame memory FR-M1, and the first still picture signal stored in the frame memory FR-M1 is read out therefrom to provide a first display signal as shown in FIG. 1-I. Then, an extraced still picture signal formed of every other picture elements in the horizontal and vertical directions of the first input still picture signal is read out and is written in a first memory area of 1/4 frame of the other frame memory FR-M2. The written still picture signal is then read out to provide a second display signal as shown in FIG. 1-II.
A second input still picture signal (for example, a still picture signal representing "B") is written in one frame memory FR-M1, and the second still picture signal written in the frame memory FR-M1 is read out to provide a third display signal (FIG. 1-III). Then, an extracted still picture signal formed of every other picture elements in the horizontal and vertical directions of the second input still picture signal is read out and is written in a second memory area of 1/4 frame of the other frame memory FR-M2. Also, the first and second extracted still picture signals are respectively read out to provide a fourth display signal.
The above-mentioned signal processings are repeatedly carried out hereinafter, whereby an extracted still picture signal of a third still picture signal (for example, a still picture signal representing "C", though not shown) and an extracted still picture signal of a fourth extracted still picture signal (for example, a still picture signal representing "D", though not shown) are sequentially written in third and fourth frame memory areas of 1/4 frames of the other frame memory FR-M2, and then the first to fourth extracted still picture signals are read out and are supplied to a monitor receiver as a final display signal.
An example of a prior-art still picture signal editing or processing apparatus which edits or processes a still picture signal by using two field memories FL-M1 and FL-M2 will be described.
A first input still picture signal (for example, a still picture signal representing "A") is written in one first field memory FL-M1, and the still picture signal written in the field memory FL-M1 is read out to provide a first display signal (FIG. 2-I). Then, an extracted still picture signal formed of every other picture elements in the horizontal and vertical directions of the first input still picture signal is read out and is written in a first memory area of 1/4 frame of the other second field memory FL-M2. Also, the still picture signal thus written in the second field memroy FL-M2 is read out to provide a second display signal as shown in FIG. 2-II.
A second input still picture signal (for example, a still picture signal representing "B") is written in one field memory FL-M1, and the second still picture signal written in the first field memory FL-M1 is read out to provide a third display signal (FIG. 2-III). Then, an extracted still picture signal formed of every other picture elements in the horizontal and vertical directions of the second input still picture signal is read out and is written in a second memory area of 1/4 field of the second field memory FL-M2. Also, the extracted still picture signals of the first and second still picture signals are read out to provide a fourth display signal.
The above-mentioned signal processings are repeatedly carried out hereinunder, whereby an extracted signal of a third still picture signal (for example, a still picture signal representing "C", though not shown) and a fourth extracted still picture signal (for example, a still picture signal representing "D") are sequentially written in third and fourth 1/4 field memory areas of 1/4 field of the second field memory FL-M2, respectively. Then, the first to fourth extracted still picture signals are read out and are supplied to the monitor receiver as the final display signal.
The prior-art still picture signal processing apparatus explained with reference to FIG. 1 employs the two frame memories FR-M1 and FR-M2 so that the display signal, provided by reading the extracted still picture signals shown in FIGS. 1-I and 1-IV from the frame memory FR-M2, is high in resolution. This prior-art still picture signal processing apparatus, however, needs two frame memories. Hence, this apparatus becomes very expensive.
The prior-art still picture signal processing apparatus explained with reference to FIG. 2 requires two field memories FL-M1 and FL-M2, namely, one frame memory so that it becomes inexpensive. In this prior-art apparatus, however, the extracted still picture signals of FIGS. 2-II and 2-IV stored in the field memory FL-M2 are read out, which provides the display signal of low resolution.